Thanks to Jay Markanich a home inspector in Northern Virginia for these duct and furance filter tips... and even the housekeeping hints.. about vacuuming and dusting.

In the previous post I discussed dusty ducts and their contents. That post has become increasingly popular! And I have received many private contacts asking for the follow up!

So, how can we prevent such dust build up in our ducts and forestall its accumulation?

First, there are two HVAC industry philosophies on household air filtration.

Second, there are many types of filters out there - ranging from disposable, to washable to electronic. Some are very cheap, others quite expensive.

Remember, an HVAC system moves and conditions air. The more it moves the more it can condition. So air returns are extremely important. Most people think of their HVAC system as one that blows air. It is more valuable to think of it as a system that RETURNS air. Volume is crucial!

Philosophy 1. Install a filter that allows more air to flow. This puts less strain on the system, moves more air and the system operates more efficiently. But, these filters remove less particulate matter from the air and the system can get dirtier faster.

Philosophy 2. Install a high-filtration filter. These of course remove more particulates from the air. But they clog more quickly and restrict air flow and need cleaning or replacement quickly. Even newly replaced, these filters cause 10 - 20 times more restriction to air flow. Therefore, they reduce efficiency, but the system stays cleaner longer.

So, which to choose?

Some news about dust! The typical family of four creates about 40 pounds of dust in a year! This comes into the house as we open windows and doors, on our clothing and shoes, and it resides in our furniture, carpets, bedding and pillows. That is a lot of dust!

Just walking through a room disturbs and releases millions, if not billions, of dust particles into the air, which is moved about as we continue to move. Sitting on the sofa releases much more, or hitting a pillow or folding a blanket - you name it! Dust is always moving about the house through the air.

TO FILTER ALL THAT FROM THE INDOOR AIR, ALL OF THE AIR WOULD HAVE TO BE EXCHANGED BETWEEN 12 AND 15 TIMES AN HOUR!

The typical HVAC system exchanges all of the air in the house only about 5 to 7 times A DAY, depending on its efficiency and size. And that is only true if you run the fan 24/7.

So your furnace/AC filter will never, that is NEVER, filter enough air to adequately to remove all those particles and allergens from the air. An expensive air filter might keep your system cleaner, and your registers, but not so much anything else.

So what can we do?

My recommendations:

1. Vacuum and dust regularly. Nobody wants to hear that! But it is true. Approximately 85% of the dust in the air falls onto the floor and furniture. Vacuuming often with a HEPA (High Efficiency Particulate Accumulation) vacuum gets a lot of it. Dusting is crucial.

2. HEPA room air cleaners can go a long way toward controlling allergens, spores, molds and mites in the house. These are most effective in bedrooms. Should you use the ozone-creating filters? My reading says no. Ozone negatively charges dust making it fall. It will land everywhere, and on you while you sleep! When you get up you disturb it again, releasing it back into the air. Ozone can also be irritating to many people's respiratory systems.

3. Shake pillows and blankets outdoors, and often! Were you the student asked to beat the chalk erasers at school? Same principle! Wash bedding regularly, particularly to control dust mites.

4. Vacuum furniture and mattresses. Spraying mattresses with Lysol or some other disinfectant helps also to control dust mites. Deodorizers do nothing toward dust mite control.

5. Replace your furnace filter regularly! How often? Once a month, except perhaps those months the system is not operating so much. And put it in the right direction! They have an arrow on them showing the way!

Information is deemed to be accurate but should be verified to your satisfaction. Information provided herein is supplied by several sources and is subject to change without notice. Opinions expressed are solely those of Maureen McCabe.